Dynamic logic circuits have been used as an effective power conservation tool in silicon MOS technology.
GaAs FETs have been used to implement static logic and memory circuits in various applications (static RAMs, adders, multipliers, etc.). However, implementation of dynamic circuits with GaAs FETs has not been as well developed as its static counterpart due to leakage of the forward biased Schottky barrier gate diode of the FETs, and the often critical timing requirements on the clock. Circuits intended for very high speed, and not very low power, have been emphasized, such as a dynamic frequency dividers and shift registers. These circuits used only the concept of the pass transistor in combination with GaAs MESFET buffered FET logic (BFL). Consequently, power dissipation was very high. The charge storage, which is the main feature of the dynamic circuit, is not fully utilized in this approach.
Charge control devices (CCDs) have been implemented by GaAs FETs and show very fast operation. However, the circuit applications available to the CCD are limited, and the need for three- or four-phase clocks increases the complexity and power dissipation. The present invention addresses the need for low power, high speed logic circuits with an acceptable noise margin. While GaAs enhancement or depletion mode MESFETs satisfy the first two criteria in static logic circuits, it cannot produce high-yield LSI/VLSI circuits due to its low noise margins (&lt;200 mV).
Domino circuits were first developed for silicon CMOS as a means of increasing speed and circuit density. A domino circuit, as the term is used herein, refers to a single stage, the function of which is to propagate to the next stage in a chain of stages the logic information developed from information introduced into the circuit, such as in a 2-input or 4-input AND gate. Dynamic logic circuits have been used as an effective power conservation tool in silicon MOS technology. See R. H. Krambeck, C. M. Lee and H. S. Low, "High-speed compact circuits with CMOS, " IEEE J. Solid State Cir., SC-17, No. 3, pp 614-619, June 1982.